Electric guitar incorporating improved electromagnetic pickup assembly, and improved circuit means



C. L. FENDER Dec. 6, 1966 ELECTRIC GUITAR INCORPORATING IMPROVED ELECTROMAGNETIC PICKUP ASSEMBLY, AND IMPROVED CIRCUIT MEANS Filed March 6, 1964 2 Sheets-Sheet 1 INVENTOR. CLAPENCE L. FENDER BY W /%g A r TOENEXS Dec. 6, 1966 c. L. FENDER ELECTRIC GUITAR INCORPORATING IMPROVED ELECTROMAGNETIC PICKUP ASSEMBLY, AND IMPROVED CIRCUIT MEANS Filed March 6, 1964 2 Sheets-Sheet 2 S Q N RM N mN E W m V T WL h A 5 m M 6 & w l

3 2 E m K WA ADM W m w 0 0 6 0 L 5 United States Patent 3,290,424 ELECTRIC GUITAR WCORPORATING IMPROVED ELECTROMAGNETIC PICKUP ASSEMBLY, AND IMPROVED CIRCUIT MEANS Clarence L. Fender, Fullerton, Calif, assignor, by lnesne assignments, to Columbia Records Distribution Corp., New York, N.Y., a corporation of New York Filed Mar. 6, 1964, Ser. No. 349,800 Claims. (Cl. 841.16)

This invention relates to an electric guitar incorporating an improved electromagnetic pickup assembly. The invention also relates to improved circuit means for adjusting the relationships between various individual pickup elements.

An object of the present invention is to provide a practical, commercial, and economical pickup assembly incorporated in a guitar or the like, which assembly is so sensitive that it may be disposed on the order of one-half inch or more from the strings, and completely concealed beneath the pick guard or face plate of the instrument, yet responds in a musically satisfactory manner to all generated frequencies including high frequencies.

Another object of the present invention is to provide a guitar incorporating a completely concealed pickup assembly which responds equally well to the outboard and inboard strings of a guitar.

Another object is to provide an improved switching system adapted, when employed in combination with a plurality of individual pickup elements, to achieve novel sound effects in a simple and economical manner, and without effecting an excessive change in the volume of the response.

Another object is to provide a plurality of pickup components connected with phase-reversing switches, and having reversed magnetic polarity.

Another object is to provide an improved pickup assembly incoporating large numbers of permanent-magnet pole pieces, and also to provide the combination of such a pickup assembly with circuit means for altering the relationships between individual pickup components of the assembly.

These and other objects will become apparent from the following detailed description taken in connection with the accompanying drawings in which:

FIGURE 1 is a plan view illustrating a guitar having mounted thereon the pickup assembly of the present invention, all portions of the assembly being concealed excepting for various electrical control elements;

FIGURE 2 is an enlarged plan view of the body portion of the guitar shown in FIGURE 1, the pickup components being illustrated in dashed lines;

FIGURE 3 is an enlarged plan view illustrating one pickup component of the assembly, the face plate which normally conceals such pickup component being removed, the coil portion of such component being shown in dashed lines;

FIGURE 4 is an enlarged transverse sectional view taken on line 44 of FIGURE 2;

FIGURE 5 is a sectional view taken on line 5-5 of FIGURE 4; and

FIGURE 6 is a schematic wiring diagram illustrating the circuit means for adjusting the phase and other relationships between individual components of the assembly.

Referring first to FIGURES 1 and 2 of the drawings, the invention is illustrated as incorporated in an electric guitar 10 having a body 11, neck 12 and head 13. Body 11, which is illustrated as being of the solid type although it may be hollow, has a generally fiat upper surface or face 14. Six guitar strings 16-21 are mounted in tensioned relationship over surface 14 and also over neck 12, being stretched between tuning screws 22 on head 13 "ice and a suitable bridge and tremolo device 23 on body 11. A suitable device 23 includes a bridge portion 23a and a tremolo portion 23b, as described in United States Patent No. 2,972,923.

The strings 16-21 are shown in FIGURE-4 as lying generally in a plane parallel to the plane of body surface 14. It is to be understood, however, that such strings may also lie along the surface of an imaginary largediameter cylinder having a central axis which is disposed a substantial distance beneath the instrument and parallel to the axis of the instrument. It is also to be understood that the exact shape of face or surface 14 is immaterial. As shown in FIGURES 1 and 2, the strings 16-21 may diverge in a direction from head 13 to body 11, so that they are spaced much farther apart at the bridge assembly 23 than at a bridge 24 which is disposed at the junction between neck 12 and the head.

Electric guitars of the indicated type are conventionally provided with a decorative face plate or pick guard which is suitably secured to surface 14. The present face plate is indicated at 26 and is formed of plastic or other suitable non-magnetizable material. Face plate 26, which conventionally serves as a decorative background for various electrical switch elements, also serves in the present guitar to completely conceal the various pickup components 27- 30 next to be described.

As shown in FIGURE 2, four pickup components 27- 30 are illustrated as mounted in spaced relationship, longitudinally of strings 16-21, beneath the face plate 26. It is a feature of the present invention that these pickup components 27-30 may be substantially identical to each other, for mass production at a very low cost, despite the fact that the strings 16-21 diverge as previously indicated. However, as will be indicated subsequently, in some of the pickup components all of the north poles may be adjacent the strings, whereas in others of the pickup components the south poles may be adjacent the strings. Since all of the pickup components are substantially identical, only one, No. 28, will be described in detail.

As best shown in FIGURES 3-5, each pickup component comprises two rows of permanent-magnet pole pieces 31, the rows of pole pieces being parallel to each other and transverse to the strings 16-21. Each row contains eight pole pieces 31, six of such pole pieces being generally beneath the respective strings 16-21. The remaining two pole pieces in each row are outboard of the strings, there being one outboard pole piece at each end of each row. The pole pieces in each row are spaced substantially equal distances apart. Thus, each row of pole pieces is similar to what would be found in a conventional pickup for an eight-stringed guitar.

The pole pieces are preferably elongated cylindrical permanent magnets. The axes of such magnets are perpendicular or substantially perpendicular to the plane of the strings. All portions of all of the magnets lie on only one side of the plane of the strings, and are spaced a substantial distance from such plane.

The spacing between the two rows of pole pieces is suificiently small that the pole pieces (which have the same magnetic polarity, as will be described below) definitely interact with and repel each other, bunching up the lines of magnetic force in such manner that many lines extend upwardly from face plate 26 a much greater distance than would be the case if only one row were present. Because of this bunching-up of the lines of magnetic force, the strings 16-21 may be spaced on the order of one-half inch from the upper ends of the pole pieces 31, and still achieve a highly satisfactory musical response.

As shown in FIGURE 3, the two rows of pole pieces may be spaced apart a distance generally equal to the spacing between adjacent pole pieces in each row,,so that the four pole pieces associated with each two adjacent strings form a rectangle which approximates a square. It is not necessary that the parallel rows of pole pieces be perfectly perpendicular to the strings as viewed in FIG- URE 3, it being possible that such rows are somewhat oblique to the strings. Also, the rows may be somewhat curved.

As indicated above, it is essential to the invention that the magnets in both rows have corresponding magnetic poles disposed adjacent thestrings. Thus, in the illustrated pickup component 28 all of the north poles are adjacent the strings.' The same is true of the pickup component 30. However, it has been found that all of the south poles in each of the pickup components 27 and 29 should be adjacent the strings. This minimizes the magnetic interaction between the various pickup components 27-30, and permits such components to be disposed surprisingly close to each other.

To state the above in another manner, corresponding poles of alternate pickup components 27, 29 and 28, 30 are adjacent the strings. Because of such reversal of magnetic polarity, the coils of adjacent pickups should be reverse connected, as shown in FIGURE 6, thereby permitting the associated switches (to be described subsequently) to produce corresponding circuit effects when in corresponding positions.

In the illustrated embodiment, the sixteen pole pieces in each pickup component are inserted through corresponding openings in plastic or fibrous sheet-s 32 and 33, for example in a press-fit relationship. A single coil 34 is wound between the sheets 32 and 33, and around all of the pole pieces 31. Such coil comprises a large number of turns of fine wire, for example ten thousand turns of number 42 plain enamel-coated wire.

A plastic or fibrous casing 36 is mounted over the sheets 32 and 33 around coil 34, having at the end portions thereof apertured lugs 37 adapted to receive screws 38. The entire pickup component is mounted on a mass 39 of foam rubber or plastic, in a recess 41 which is formed in body 11 beneath the face plate 26. The screws 38 extend downwardly through lugs 37 into the body, and may be adjusted to determine the exact elevation of the pickup component.

Normally, the construction is such that the upper surface of casing 36, through which the upper ends of the permanent-magnet pole pieces 31 extend, is adjacent the lower surface of face plate 26. However, the screws 38 may be turned to create a space between the pole pieces and the face plate 26, if desired and in order toadjust the response.

It is emphasized that the illustrated manner of mounting the pole pieces and coil is only given by way of illustration,

it being possible to mount the pole pieces and coil beneath the face plate in many other ways.

Referring next to FIGURE 6, improved circuitry is illustrated for connecting all of the pickup components 27-30 into a pick-up assembly adapted to supply signal to a suitable output amplifier and loudspeaker means which is schematically indicated at 43. In the illustrated embodiment, the pickup components 27-30 have associated therewith suitable three-position double-pole selector switches 44-47, respectively, each such switch having two mechanically-interconnected poles or arms. It is to be understood, however, that such switches may be replaced by two-position switches wherein the poles may also be shifted to blank positions-in engagement with neither contact. It is also to be understood that other switches may be employed, for example switches of the slider type as distinguished from the pivoted-pole type.

Stated more definitely, the coils 34 are connected to corresponding terminals 50 (for example, the right terminals) in the associated switches 44-47. Furthermore, the coils are connected to the center treminals 51 in such switches. The relationship is such that when the switch arms of any switch 44-47 are both in engagement with 4 contacts 50, the coils 34 are connected in a manner which is the reverse of the manner of connection when the switch arms are in engagement with contacts 51. When the arms of any switch are shifted to the third position, which may be blank or blind as previously noted, the associated coil is out of circuit.

One set of poles or switch arms of the switches 44-47 is connected through a lead 54 to ground, whereas the remaining set of poles or arms is connected through a lead 55 to ground. The latter lead has interposed therein a resistor 56 which forms part of a potentiometer, the slider 57 of such potentiometer being connected to the input of the amplifier and loudspeaker 43. A suitable tonecontrol means may be provided, in the form of a rheostat 58 connected between slider 57 and ground, such circuit extending through a capacitor 60 whereby the setting of the rheostat determines the proportion of the high-frequency components which are bled to ground.

-In the circuit shown in FIGURE 6, the coils 34 of the pickup components 27-30 are connected in parallel-circuit relationship as distinguished from a series-circuit relationship. It has been discovered that, the parallel form of connection is superior to the series, one reason being that the switches and associated circuitry may be more simple and economical in that there is no necessity for providing jumpover connections when one or more of the coils 34 is to be left out of the circuit.

More importantly, the parallel mode of connection improves the sounds which result when the various coils are connected in desired relationships. Also, the parallel manner of connection causes the variation in the volume of the response to remain within reasonable limits when the relationship between the pickup components is changed. This is to be contrasted with the series mode of connection, in which the volume varies considerably when additional coils are connected into (or omitted from) the circuit.

The control knobs associated with the switches 44-47 are indicated at the lower portion of FIGURE 2. The control knobs associated with slider 57 and rheostat 58 are indicated at the upper-right portion of FIGURE 2.

OPERATION There first will be described the operation of the various switching means 44-47 in connecting the 60115 34 of pickup components 27-30 in desired phase relationships. Thereafter, the operation of the individual pickup components 27-30 will be considered, particularly in relation to the means by which such components may be disposed beneath the face plate 26 and still achieve an excellent highfrequency response.

The various selector switches 44-47 are operated in such manner as to connect the coils 34 of the pickup components 27-30 in desired phase relationships. Any coil 34 may be connected into or out of the circuit. Furthermore, each coil may be reversed relative to each other coil.

Because the pickup components are disposed beneath different portions of the strings 16-21, being spaced longitudinally thereof, such pickup components sense (when the magnetic fields are disturbed due to vibration of the strings) different harmonics in different degrees. It follows that the sensing of such harmonics in different degrees, and the manipulation of the phase relationships between the coils 34, causes the instrument to produce different types of sounds. For example, the instrument may be caused to sound much like a banjo.

The voltage generated in the coils in response to string vibration, and received at slider 57 of the potentiometer, is passed to the output amplifier and loudspeaker 43, the higher-frequency components being bled through capacitor 60 to ground in various degrees depending upon the setting of rheostat 58.

It has been discovered that when the coils 34 of two pickup components, for example components 27 and 28, are out of phase relative to each other, the resulting sound is much more brilliant (dominated by the higher-frequency components) that when such coils are in phase relative to each other. It is to be understood that the characteristics of the string vibrations change rapidly in a direction away from the bridge element 23a, the change beinggreater relative to the higher-frequency components than relative to the lower-frequency components. Because the change in higher-frequency components is greater, the response is more brilliant when the pickups connected in the circuit are in out-of-phase relationship relative to each other.

It has also been discovered that when the coils 34 of the pickups 27 and 28 (relatively adjacent bridge 23a) are in out-of-phase relationship relative to each other, the generated sound is softer than when the coils 34 of pickup components 29 and 30 are the ones Which are connected in out-of-phase relationship.

It is a feature of the invention that the various pickup components 27-30 may be disposed relatively adjacent each other, and still produce unusual and desirable sound effects. One reason for this is the previously indicated reversal of the poles of components 28 and 30 relative to the poles of components 27 and 29. It is also a feature of the invention that, as previously emphasized, the volume of response is not changed excessively as various pickup components are connected into or out of the circuit.

As an example, let it be assumed that the poles of the switches 44-47 are disposed as illustrated in FIGURE 6. Pickup component 27 is then in phase with component 30, but out-of-phase relative to component 29. Thus, component 29 is out-of-phase relative to components 27 and 30. Component 28 is not in the circuit. By employing this and numerous other combinations of phase relationships, using various desired ones of the pickup components, numerous novel sound effects are achieved.

Proceeding next to a description of the operation of each individual pickup component, the positioning of all of the like poles of permanent-magnet pole pieces 31 adjacent each other creates a repelling action which causes the lines of magneticforce to extend upwardly from the ends of the magnets a much greater distance than would otherwise be the case. If each of the pole pieces 31 were disposed remote from all other pole pieces, the majority of the lines of magnetic force would take the shortest distance between the north and south poles, and would not extend a substantial distance upwardly from the ends of the poles. The situation would then be generally the same as that occurring in a conventional electromagnetic pickup, in which there is only a single row of pole pieces so that any bunehing action caused by the proximity of like poles is insubstantial. It follows that in conventional apparatus the pickups must be exposed, and must be disposed closely adjacent the plane of the strings where they may interfere with the action of the musician playing the instrument.

In the present pickup, the degree of bunching and consequent upward extension of the lines of magnetic force is very substantial and important, due tothe fact that the bunehing occurs in the entire region between the two rows of pole pieces. Stated otherwise, the region defined by each rectangle or square (the corners of which are formed by the ends of the pole pieces as viewed in FIG- URE 3) constitutes an effective region where the repulsion is very strong, so that large numbers of lines of force are crowded upwardly into the vicinity of the strings 16-21. Accordingly, the present pickups may be concealed beneath face plate 26, which is thin and non-magnetic, yet the strings may be disposed on the order of one-half inch or more from the pickup.

Were it not for the presence of the outboard p-ole pieces 31, namely the end pole pieces in each row, the pickup action relative to the outboard strings 16 and 21 would be undesirably weak. This is because such outboard strings would be subjected to the action of the lines of force which are crowded upwardly due to the interaction of those pole pieces lying beneath strings 16 and 17 on the one hand, and 20 and 21 on the other hand. However, there would be relatively little bunehing of the lines of magnetic force lying outboard from the pole pieces which are disposed beneath strings 16 and 21. Because of the presence of the pole pieces at the ends of the rows, bunching occurs relative to strings 16 and 21 just as it does relative to the inboard strings 17-20. It follows that the response relative to all of the strings 16-21 is relatively equal.

Because of the fact that the magnets 31 are small, the high-frequency response of the present pickup is at least equal to that of conventional pickups incorporating .a single row of permanent magnets. The high-frequency response is substantially better than in pickups incorporating bar-type magnets because of the large mass of such magnets.

A further advantage of the present pickup is that it may be manufactured economically, 'with substantially the same type of apparatus as is employed to manufacture conventional pickups having only a single row of magnets. The additional expense involved in providing an extra eight pole pieces is compensated for, at least to a substantial degree, by savings effected by mounting the pickups beneath the face plate 26. Thus, for example, it is possible to omit the outer casing 36, screws 38, and sponge rubber 39, instead merely disposing the two fibrous sheets 32 and 33 and associated elements 31 and 34 in a suitable recess. It will be appreciated that the absence of the need for a decorative casing, and associated mounting elements, largely offsets the increased price inherent in employing eight extra magnets.

It is emphasized that the magnets or pole pieces 31 may not be disposed excessively far apart, or else they will act independently and will not project the magnetic fields upwardly to the strings. On the other hand, the magnets should not be disposed sufiiciently close together to act as a single magnet. Thus, there is a range of spacings, readily determinable by experiment, through-which the repulsion action between like poles is such that the magnetic fields project upwardly surprisingly far, as stated previously. As an illustration, each magnet may be 7 inch in diameter, and may be spaced A inch (between adjacent regions, not on centers) from each other magnet. The magnets may be Alni'co, and about /3 inch long.

The foregoing detailed description is to be clearly understood as given by way of illustration and example only, the spirit and scope of this invention being limited solely by the appended claims.

I claim:

1. A guitar, which comprises:

a body having a face,

a neck connected to said body and extending outwardly therefrom,

six magnetizable and generally-parallel guitar strings extending over said neck and over said face,

said strings lying generally in a single plane parallel to said face,

means to connect the ends of said strings to said body and to the end of said neck remote from said body,

a plurality of electromagnetic pickup components mounted on said body in spaced relationship longitudinally of said strings whereby to sense the different harmonics generated at different longitudinal points along said strings,

each of said pickup components comprising a plurality of permanent-magnet elements disposed on one side only of said plane of said strings,

said elements being spaced from each other longitudinally of said strings but being disposed sufficiently close to each other that said elements interact strongly with each other, like poles of said elements being disposed adjacent said plane of said strings, alternate ones of said pickup component-s being disposed with the north poles thereof relatively adjacent said plane of said strings,

the remaining alternate ones of said pickup components being disposed with the south poles thereof relatively adjacent said plane of said strings,

each of said pickup components further comprising coil means operably associated with said permanent-magnet elements, and

switching and circuit means to connect said coil means of said pickup components to an amplifier and loudspeaker means,

said switching and circuit means being adapted to selectively reverse the phases of said components relative to each other,

said switching and circuit means also being adapted to disconnect selected ones of said pickup components from said amplifier and loudspeaker means.

2. A guitar, which comprises:

a body having a face,

a neck connected to said body and extending outwardly therefrom,

six magnetizable and generally-parallel guitar strings extending over said neck and over said face,

said strings lying generally in a single plane parallel to said face,

means to connect the ends of said strings to said body and to the end of said neck remote from said body,

a plurality of electromagnetic pickup components mounted on said body in spaced relationship longitudinally of said strings whereby to sense the different harmonics generated at different longitudinal points along said strings, and switching and circuit means to connect all of said pickup components to an amplifier and loudspeaker means,

said switching and circuit means being adapted to selectively reverse the phases of said components relative to each other,

said switching and circuit means also being adapted to disconnect selected ones of said pickup components from said amplifier and loudspeaker means, I

said switching and circuit means connecting said pickup components in parallel-circuit relationship whereby to permit achievement of novel sound effects in a simple manner and without affecting excessively the volume of the signal supplied to said amplifier and loudspeaker means.

3. The invention as claimed in claim 2, in which tonecontrol means are incorporated in said switching and circuit means to vary the proportion of the higher-frequency audio components supplied to said amplifier and loudspeaker means.

4, A guitar, which comprises:

a body having a face,

a neck connected to said body and extending outwardly therefrom,

six magnetizable and generally-parallel guitar strings extending over said neck over said face,

said strings lying generally in a single plane parallel to said face,

means to connect the ends of said strings to said body and to the end of said neck remote from said body, and

a plurality of electromagnetic pickup components mounted in said body beneath said face and in spaced relationship longitudinally of said strings whereby to sense the different harmonics generated at different longitudinal points along said strings,

each of said pickup components comprising a first row of elongated permanent-magnet pole pieces, said first row being disposed perpendicular to said strings, the pole pieces in said first row being gen- Q o erally perpendicular to the plane of said strings, said first row including a number of pole pieces corresponding to the number of said strings, the pole pieces in each of said number being disposed respectively beneath said strings, said first row further including two outboard pole pieces disposed, respectively, outwardly from the outboard ones of said strings, each of said pickup components further comprising a second row of elongated permanent-magnet pole pieces,

said second row corresponding to said first row relative to the construction, location and number of the pole pieces therein except that said second row is offset longitudinally of said strings a distance corresponding generally to the spacing between adjacent ones of said pole pieces in each row, whereby each set of two adjacent strings has four pole pieces disposed therebeneath and defining generally a square, all of said pole pieces in both said first row and said second row having corresponding poles disposed adjacent said strings, each of said pickup components further comprising a single coil of fine wire mounted around all of said pole pieces in both of said rows, all of the pole pieces in alternate ones of said pickup components being oriented with the north poles thereof relatively adjacent said strings, and all of the pole pieces in the remaining alternate ones of said pickup components "being oriented with the south poles thereof relatively adjacent said strings. 5. A guitar, which comprises: a body having a face, a neck connected to said body and extending outwardly therefrom, six magnetizable and generally-parallel guitar strings extending over said neck and over said face,

said strings lying generally in a single plane parallel to said face, means to connect the ends of said strings to said body and to the end of said neck remote from said body, a plurality of electromagnetic pickup components mounted in said body beneath said face and in spaced relationship longitudinally of said strings whereby to sense the different harmonics generated at different longitudinal points along said strings,

each of said pickup components comprising a first row of elongated permanent-magnet pole pieces, said first row being disposed perpendicular to said strings, the pole pieces in said first row being generally perpendicular to the plane of said strings, said first row including a number of pole pieces corresponding to the number of said strings, the pole pieces in each of said number being disposed respectively beneath said strings, said first row further including two outboard pole pieces disposed, respectively, outwardly from the outboard ones of said strings, each of said pickup components further comprising a second row of elongated permanent-magnet pole pieces,

\ said second row corresponding to said first row relative to the construction, location and number of the pole pieces therein except that said second row is offset longitudinally of said strings a distance corresponding gen erally to the spacing between adjacent ones of said pole pieces in each row,

whereby each set of two adjacent strings has four pole pieces disposed there'beneath and defining generally a square, all of said pole pieces in both said first row and said second row having corresponding poles disposed adjacent said strings, each of said pickup components further comprising a single coil of fine wire mounted around all of said pole pieces in both of said rows, and switching and circuit means to connect all of said pickup components to an amplifier and loudspeaker means,

said switching and circuit means being adapted to selectively reverse the phases of said components relative to each other, said switching and circuit means also being adapted 10 to disconnect selected ones of said pickup components from said amplifier and loudspeaker means, said switching and circuit means connecting said pickup components in parallel-circuit relationship.

References Cited by the Examiner UNITED STATES PATENTS 2/1965 Freeman 84-116 2,892,371 6/1959 Butts 84-1.16 2,961,912 11/1960 Meola 841.16 X

ARTHUR GAUSS, Primary Examiner. D. D. FORRER, Assistant Examiner. 

2. A GUITAR, WHICH COMPRISES: A BODY HAVING A FACE, A NECK CONNECTED TO SAID BODY AND EXTENDING OUTWARDLY THEREFROM, SIX MAGNETIZABLE AND GENERALLY-PARALLEL GUITAR STRINGS EXTENDING OVER SAID NECK AND OVER SAID FACE, SAID STRINGS LYING GENERALLY IN A SINGLE PLANE PARALLEL TO SAID FACE, MEANS TO CONNECT THE ENDS OF SAID STRINGS TO SAID BODY AND TO THE END OF SAID NECK REMOTE FROM SAID BODY, A PLURALITY OF ELECTROMAGNETIC PICKUP COMPONENTS MOUNTED ON SAID BODY IN SPACED RELATIONSHIP LONGITUDINALLY OF SAID STRINGS WHEREBY TO SENSE THE DIFFERENT HARMONICS GENERATED AT DIFFERENT LONGITUDINAL POINTS ALONG SAID STRINGS, AND SWITCHING AND CIRCUIT MEANS TO CONNECT ALL OF SAID PICKUP COMPONENTS TO AN AMPLIFIER AND LOUDSPEAKER MEANS, SAID SWITCHING AND CIRCUIT MEANS BEING ADAPTED TO SELECTIVELY REVERSE THE PHASES OF SAID COMPONENTS RELATIVE TO EACH OTHER, SAID SWITCHING CIRCUIT MEANS ALSO BEING ADAPTED TO DISCONNECTED SELECTED ONES OF SAID PICKUP COMPONENTS FROM SAID AMPLIFIER AND LOUDSPEAKER MEANS, SAID SWITCHING AND CIRCUIT MEANS CONNECTING SAID PICKUP COMPONENTS IN PARALLEL-CIRCUIT RELATIONSHIP WHEREBY TO PERMIT ACHIEVEMENT OF NOVEL SOUND EFFECTS IN A SIMPLE MANNER AND WITHOUT AFFECTING EXCESSIVELY THE VOLUME OF THE SIGNAL SUPPLIED TO SAID AMPLIFIER AND LOUDSPEAKER MEANS. 